Dear all,

this morning I changed the tires and the rear shocks of my 2003 s-type.

When I wanted to start it, no cranking. Everything else works out, the instrument cluster is illuminated but when I turned the key, nothing happens at the starter level. The head light switched off, the radio switched off as usual when cranking, but no starter motor.

I suspected the PATS and I looked at the light. It was illuminated during 3s and then switched off, so the PATS seems to works fine.

I looked at the DTC and I got P1260 and P0860. The P0860 is strange since the gear selector works fine: when I move it, the gear light move as well (P is illuminated, then R, then N, ...). I tried to start it in N, same things. I cleared these codes, nothing was better.

Do you have an idea of what may happen ?

Thanks a lot,

Laurent

 

Have you checked the two bolts for the shift cable on the side of the gearbox? They may be loose or missing, which can cause the vehicle not to start.

 

I did not check it but we managed to move the car in the N position. I guess if this cable was not well attached we would be unable to set the N position ?

 

Yes, that is correct.

 

I'd pray it's either the 2 bolts (unlikely), the brake switch/gearbox interlock or low battery.

P1260 if a current code is worth reading up on in the jag docs / workshop manual (free downloads).

 

How can I est the switch/gearbox interlock ?

Since the steering column unlocks, can it be the key transponder ? Because I had another key 500 miles away ... I can go take it but if it's not likely the key, it would be useless ...

 

Not sure I can be much help here, but check fuse F15 in the primary junction box, inside the cabin just forward of the right front door.

 

So I perform some others tests (I did not test the F15 fuse, will do tomorrow).

For the first time, I saw a B1600 code : Passive anti-theft system ignition key transponder signal is not received. I got rid of it, it does not come again but the problem remains.

I read the data flow of the instrument pack, here the values:
- Ignition off / unlock switch: NO;
- Ignition crank switch: NO when the key is in II position, YES when the key is in III position;
- Battery voltage: 11.7V. I plug a charger tonight;
- Key in ignition switch: NO => weird value isn't it ?
- Passive anti-theft system number of ignition key codes supported: 2;
- Gear selector not in park switch: FALSE when the selector is on P, TRUE on other values;
- Passive anti-theft system status: ENABLED;
- Passive anti-theft system status - master key present: YES;
- Passive anti-theft system status - powertrain control module verification: YES.

I do not understand why the key in ignition switch is NO and I do not understand why the PATS status is ENABLED althought the PATS red light was illuminated during 3s and then switched off.

Any clues ?

Thanks a lot,

Laurent

 

P1260 on older jags is almost always a forgotten key problem. program the key in IDS, you will need 2. in dealer settings you can enable a one time drive if you need to move the car


i recommend buying 4 spares and having them all cut

 

Hello,

I made some tests:
- first, I erased the p1260 code which does not come back again;
- I tried to insert the key into the ignition switch with aluminum foil around the key => I got a PATS error with the red light blinking, the fuel pump did not run and the steering column did not unlock;
- I tired to insert the key without the aluminum foil => the PATS led was OK, the steering column unlocked and the fuel pump ran;
- The fuse F1 and F15 in the junction box are good.

Question: do you think the car is still immobilized because of the PATS ?

If no, should I open a new thread stating the car does not crank ?

Thanks,

Laurent

 

Doesn't sound immo.

 

Thanks JagV8. Where can I investigate now ? The fuses are OK, the relays are OK, there is not DTC ...

Any clue ?

 

Sounds like figure out why the starter doesn't spin.

 

Hi there,

some updates. I opened the starter relay, put the ignition switch in the position II and manually activate the starter motor:




and the engine start. I can drive some miles without any issues.

After switching it off, I cannot switch it on again via the key but I start again manually.

Any idea ?

 

Wow, that's some excellent troubleshooting. Sounds like you are hot on the trail.

Apparently the starter relay is not receiving the command to energize. Check fuse F1 at the primary junction box. This is the small hidden fuse panel inside the cabin, outboard of the US front passenger's feet.

I've got some other ideas if that is good, but that is first. But for now, breakfast calls. Strawberry waffles, mmmm...

 

Okay, I'm back home now and burping up breakfast. Just as delicious on the return trip...

Have you tried swapping in a known-good relay? R6 should be a good donor, for wiper high/low. If your wipers work on all speeds, try that relay and see what happens.

Next is to check for power and ground at the starter relay socket. You will need a helper to hold the key in the start position while you read the meter. Socket #1 is battery power via the ignition switch and fuse F1 at the primary junction box. Socket #2 is ground via the ECM.

IIRC, the sockets aren't labeled but the prongs on the relay are. You'll have to figure out which socket is which by looking at the bottom of the relay.

 

Hello Karl,

I checked the fuse F1. It's correct. I checked the voltage on the F1 on both sides, it's 0V either in cranking position or not. According to the wiring diagram, F1 should be energized when the ignition key is in III:




I got no current between this fuse and the ground. This is weird because according to the instrument pack data stream, the "Ignition crank switch" is ON when the ignition switch is in III position.

I checked the voltage at the R20 relay (starter motor relay). I got 0V on both command sockets, whatever the position of the ignition key is. I tried to swap it with R21 but nothings happened.

I drove 100mi this evening and everything is working well (cruise control ...) which permit me to think there is no connection issues between the TCM, ECM, ...

Laurent

 

Very good troubleshooting process thus far.

Based on the tests you've performed and the results, especially in post 17, it may now be time to inspect the wiring loom for damage, or broken/corroded/loose connections.

 

I bet you are closer than you realize. Your results point to a failure of that pole of the ignition switch, or a broken wire between the switch and fuse F1.

To test, turn the key to run but not start. Connect a test jumper between battery power (from another fuse?) and fuse F1. You should be able to reach the little recessed test points on the head of the fuse.

If the starter now engages, that points to a problem getting power to F1. The test lead mimics turning the key to start.

 

Hello NBcat and Karl,

just to be on the same page:
- RUN is the key in position II;
- START is the key in position III.

Is-it correct ?

If yes:
- when I'm in RUN mode, what should be the voltage on F1 ? 12 ? 0 ?
- if in RUN mode, the voltage on F1 is 12v, it means the ECM should send 12V on the other side of the starter relay (R20), correct ?
- in START mode, the ECM put on side of the starter relay (R20) to the ground.

Are these assumptions correct ? If yes, I've two issues because I read 0 on both side of the starter relay when I'm in RUN mode ...

Thanks again,

Laurent